I did not see the Prophet ﷺ reciting (the Qur'an) in the night prayer while sitting except when he became old; when he used to recite while sitting, and when thirty or forty verses remained from the Sura, he would get up and recite them and then bow. (Using translation from Bukhārī 1148)
مَا رَأَيْتُ النَّبِيَّ ﷺ يَقْرَأُ فِي شَيْءٍ مِنْ صَلَاةِ اللَّيْلِ جَالِسًا حَتَّى إِذَا كَبِرَ قَرَأَ جَالِسًا حَتَّى إِذَا بَقِيَ عَلَيْهِ مِنَ السُّورَةِ ثَلَاثُونَ أَوْ أَرْبَعُونَ آيَةً قَامَ فَقَرَأَهُنَّ ثُمَّ رَكَعَ